Class 1-D. Sae Chabashira: Homeroom teacher of Class 1-D. A cold female teacher. Kiyotaka Ayanokoji: A manufactured genius hiding his true abilities. Male. Suzune Horikita: Leader of Class D, excellent grades, has personality issues. Female. Kikyo Kushida: Caring, an idol-like figure. Female. Kei Karuizawa: A hysterical girl. Yosuke Hirata: A handsome pacifist. Male. Ken Sudo: A delinquent. One of the "Three Idiots of Class D." Male. Haruki Yamauchi: A liar. One of the "Three Idiots of Class D." Male. Kanji Ike: No sense of delicacy. One of the "Three Idiots of Class D." Male. Rokusuke Koenji: Slicked-back hair, a self-centered scion. Chiaki Matsushita: A curious girl hiding her abilities. Maya Sato: A gyaru, innocent at heart. Female. Airi Sakura: A girl with an outstanding figure. Haruka Hasebe: A girl who doesn't mind being alone. Teruhiko Yukimura: A glasses-wearing boy with excellent grades but poor at sports. Akito Miyake: A quiet former delinquent obsessed with archery. Male. Satsuki Shinohara: A girl who livens up the mood. Mei-Yu Wang: A Chinese exchange student, poor at sports but good at English. Female. Kayano Onodera: A girl who is good at swimming.

*Forty students from Advanced Nurturing High School's Class 1-D and their homeroom teacher, Sae Chabashira, were suddenly transported into an unfamiliar forest one day.

Spreading out before them was a vast forest filled with flora and fauna they had never seen. Smartphones were useless, and there was no way to know how to return. The only saving grace was that everyone could understand and speak the local language. Furthermore, each of them possessed a mysterious [Talent] derived from their own personality and traits. However, they knew neither the true nature nor the usage of these powers. Since they couldn't even grasp the dangers of this unknown land, reckless solo action had to be avoided. The students confirmed each other's safety and aimed to escape the forest, relying on Chabashira's instructions and their own judgment.

Upon reaching roads and villages, they learned through interaction with the locals that this was a different world where swords, magic, monsters, and labyrinths existed. Furthermore, in a large city, they heard a legend that conquering the labyrinths found across the world and obtaining the "Labyrinth Core" deep within would grant a single wish. There was no certain evidence that the Core existed or that it truly had the power to grant wishes. Nevertheless, since no other way to return to their original world could be found, it was a clue worth pursuing for them.

Most of the classmates then established the nearest labyrinth city, Walden, as their base.

The students aiming to return home had to hone their skills as explorers, earn funds, and gather information. However, not all forty students shared the same level of resolve. Suzune Horikita prioritized rationality, while Yosuke Hirata sought coordination with those around him. Kikyo Kushida utilized her social skills, and Ken Sudo and Akito Miyake tried to acquire the strength necessary for exploration. Teruhiko Yukimura looked for ways to use his knowledge and analytical skills, while Airi Sakura and Haruka Hasebe sought out what they could do. Kiyotaka Ayanokoji observed his surroundings without standing out, and Sae Chabashira acted not just to manage the students as a teacher, but for her own return and survival.

Meanwhile, some students were unable to adapt to life in another world and tried to rely on the help of others. Who would receive the rewards earned from exploration? To what extent should they support comrades in poverty? Would they risk danger to go on a rescue? Even with the common goal of returning home, the sacrifices one could make and the responsibility one demanded of others varied from person to person.

Even with the same city as their base, not everyone belonged to a single party. Some acted with those they were close to, some chose companions based on utility, and some acted alone. While living by their own judgment, they formed exploration parties as needed, exchanged labyrinth information, and sometimes clashed over conflicting interests. The human relationships built at Advanced Nurturing High School did not simply vanish just because they had come to another world.*